Rotary pressurised-fluid device with coaxial annular units having reciprocating partitions

ABSTRACT

This invention relates to a rotary pressurized-fluid device usable as a pump, a compressor or a motor, comprises first and second coaxial annular units of revolution capable of turning one relative to the other around an axis common thereto, one of said units carrying at least one piston movable in at least one cylinder formed by an annular groove is axially located in the other of said units, and divided into work-chambers by mobile partitions which slide in grooves and which are subject to the action of cams carried by said one of said units and an inlet and an outlet orifice for the fluid communicating respectively with two orifices located one on each side of said piston.

Unite States Patent 1191 1111 3,850,552 Marcel Nov. 26, 1974 [54] ROTARY PRESSURISED-FLUID DEVICE 2,691,868 10/1954 Nicolas 418/232 wITII coAxIAL ANNULAR uNITs HAVING g RECIPROCATING PARTITIONS I ma R25,818 7/1965 Krawack1 418/219 [76] Invent fi ggff g fg jf FOREIGN PATENTS OR APPLICATIONS 203,342 1/1924 Great Britain 418/6 [22] Filed: Jan. 11, 19 241,979 10/1925 Great Britain 418/6 [2]] Appl. No.: 217,024

Primary Examzner-John .1. Vrabhk Attorne A ent, 0r Firm-Cantor and Kraft [30] Foreign Application Priority Data y 8 Jan. 14, 1971 France 1 71.01087 [57] ABSTRACT Mar. 9, 1971 France 71.08052 This invention relates to a rotary pressurized fluid de 52 us. c1 418/6, 418/13, 418/162, 9 usable as a Pump a Compressor 418/219 418/261 192/58 R pr1ses first and second coaxial annular umts of revolu- 51 Int. Cl. F01c 1/00, F030 3/00, F040 1/00 capable. of one lame [58] Field of Search 418/6 13 162 177 219 around an axis common thereto, one of sa1d unIts car- 41 7 rying at least one piston movable in at least one cylinder formed by an annular groove is axially located in the other of said units, and divided into work- [56] References Cited chambers by mobile partitions which slide in grooves UNITED STATES PATENTS and which are subject to the action of cams carried by 609.027 8/1898 Hilton et a1 418/6 said one of said units and an inlet and an outlet orifice for the communicating respectively two orix fices located one oneach side of said piston. ar y 1.175.153 3/1916 Klinger 418/219 3 Claims, 26 Drawing Figures XI I 405 74 l SHEET 08 0F 12 mmuv g NIL 3151281974 FATE sum 12 0F 12! ROTARY PRESSURISED-FLUII) DEVICE WITH COAXIAL ANNULAR UNITS HAVING RECIPROCATING PARTITIONS This invention relates to rotary pressurised-fluid devices, whose general principle is that described for example in German Pat. No. 199 795, that is to devices usable as pumps, compressors or motors, and comprising two coaxial revolving units capable of turning one relative to the other around their common axis, one of these two units carrying pistons moving in cylinders forming from annular grooves of the other unit, divided into work-chambers by partitions movable in grooves and subjected to the action of cams carried by the first unit, an inlet orifice and an outlet orifice for the fluid communicating respectively with two orifices one on each side of said pistons.

In known devices of this type, one of the two units is fixed, while the other is rotary, it being possible for the rotary unit to be either the internal unit or the external unit, depending on the uses of the devices. In either case, the internal unit is integral with a central shaft of which at least one end projects out of the external unit.

In certain applications, for example, in order to rotate capstans of lifting gear, it would be very advantageous to have all the units of the motor concentric on the periphery of the base of the capstan, that is to say a motor be made available having large dimensions substantially equal to those of the capstan and the whole interior of which is an empty space.

This is why, according to the invention, the two co- According to another feature of the invention, the motor comprises a third coaxial unit arranged inside the internal unit, and also capable of turning relative to the first-mentioned two units, in a fluid-tight manner against the one contiguous with it, this third unit and the one contiguous with it being designed and set up in such a way as to have, respectively, the same individual and relative features as the first-mentioned two units.

The invention will be better understood on reading the following description and on examining the accompanying drawings, which show by way of example some embodiments of a rotary pressurised-fluid device according to the invention. These drawings show:

FIG. 1: a longitudinal half-section of a rotary pressurised-fluid device according to the invention;

FIG. 2: a partial transverse section along the line 11-4] of FIG. 1;

FIG. 3: a transverse section along the line III-III of FIG. 4, of another embodiment;

FIGS. 4 and 5: longitudinal sections respectively along the lines IV-IV and VV of FIG. 3;

FIG. 6: an elevation of a bar of partitions of the device in FIGS. 3 to 5, shown in isolation;

FIG. 7: a plan view corresponding to FIG. 6;

FIG. 8: a section along line VIII-VIII of FIG. 7;

FIG. 9: a developed view of a portion of FIG. 5;

FIG. 10: a longitudinal section along the broken line X-X of FIG. 11, of another embodiment;

FIGS. 11 and 12: transverse sections respectively along the lines XIXI and XII-XII of FIG. 10; and

FIGS. 13 to 26: function diagrams of various devices derived from that of FIGS. 10 to 12.

FIGS. 1 and 2 show a rotary pressurised-fluid device made in the form of a circular assembly whose central portion is empty, that is to say it has no shaft and may be used, for example, for controlling the rotation of a capstan.

The fixed part of the device, or stator, is made up of two rings 201, 201A, whose external marginal portions are clamped against an annular distance block or spacer 202 by means of bolts 203.

Pistons such as 206, 206A are made up of segments of cylindrical rings fixed at regular intervals, respectively, in two cylinders 207, 207A formed, respectively, by'two annular grooves of rectangular cross-section in the two opposed faces of a circular ring 208 which constitutes the rotor of the device.

Fixed tubes 211, 211A, which open into the two cylinders in the immediate vicinity of the pistons, allow the fluid to enter and leave said cylinders.

Radial mobile partitions 213 slide in radial slots 214 in the whole thickness of the rotor, and they are each actuated by a cylindrical finger 216 in the form of a rocking lever in order to avoid any possible jamming due to defects in concentricity in the different members of the device. Each of these fingers has a spherical central part 217 fitted in an axially-directed hole 218 in the rotor and two spherical end-parts 221, 222 engaged respectively in two grooves 223, 224 forming cam grooves in the two surfaces facing the two cheecks of the stator 201, 201A. For convenience of manufacture, one at least of the lateral faces of the said cam grooves is constituted by an inserted annular plate 226, 226A fixed, for example, by means of milled-head screws 227, on the corresponding cheek.

Cheek 201 of the stator has tapped holes 231 through which pins 216 may be conveniently put in place after assembly of rotor, stator and mobile partitions. In these holes there are screwed pierced plugs 232 serving as starting-points for recovering leaks of fluid.

Cavities 234, 234A in the two faces of the rotor and supplied with pressurised fluid, form hydraulic stops for axial centring of the rotorbetween the two cheeks of the stator. The device function as follows:

It will firstly be supposed that it is to operate as a motor, that is to say that it is supplied with pressurised fluid, for example, oil, brought through the connectons such as connection 211A located at the upper part of FIG. 2, that is to say on the side of the forward face of pistons 206 considered in relation to the direction of rotation of the device indicated by arrow f. The other orifices, such as the orifice 211A, which is at the lower part of FIG. 2, that is to say on the side of the rear face .of pistons 206, are connected to an appropriate return pipe.

The pressurised oil entering through the admission orifices into cylinder 207 at different points uniformly distributed on the periphery of the latter, exerts a pressure against the rear face of the radial mobile partitions 213 which are in the position closing the cylinder. The oil, bearing against the forward face of the corresponding piston 206, pushes back the partition which is immediately downstream of the latter, and thus it causes the ring 208 of the device to rotate in the direction of arrow f.

At the same time the oil trapped between the rear face of each piston 206 and the forward face of the partition located immediately upstream, as is the case for example in the vicinity of the lower part of FIG. 2, progressively decreases in volume, so that it is expelled through the corresponding outlet orifice 211A.

While the rotor of the device is turning, the radial mobile partitions 213 are subjected to the action of the cam 63 so that their castellations 207 coincide exactly with the profile of cylinder 207 and so that piston 206 can pass into the said castellation.

The device operates under excellent conditions, since it is perfectly balanced.

The couple supplied by rotor 208 is equal to the sum of the couples supplied by the pressure of the oil on the rear face of eachpartition which is opposite the forward face of a piston 206.

Naturally, if the admission and exhaust orifices are interchanged, the direction of rotation of the device is reversed.

The defice is moreover reversible, that is to say, if its rotor 208 is turned, it can be made to operate as a pump or compressor.

Another embodiment, shown in FIGS. 3 to 9, is substantially composed of:

a cylindrical stator assembly 341, formed of a main part 342 on which there is mounted by collan'ng a socket 343 positioned by a centring finger 344, and two cams 345, 346 mounted without play on the assembly 341 and positioned by pins 347 (FIG. 5). The admission and exhaust of fluid are effected through the stator;

a one-piece rotor 351. The space between the external part of the stator and the internal cylindrical coaxial part of the rotor is very small;

a connection between stator and rotor, made up of two ball bearings 352, 353 kept in place by flanges 354, 355 fixed on the rotor with the aid of screws 356, and carrying the fluid-tight joints 358, 359.

The rotor comprises annular grooves 361. These grooves and the external surface of the stator define annular cavities hereinafter called cylinders. In each cylinder there is lodged a piston 363 or 364 of a crosssection conforming to that of the cylinder and capable of sliding in a fluid-tight manner. Each piston is connected to the stator, only in the circumferential direction, by a pin 365.

The rotor likewise has, regularly spaced over its surface, axially-directed grooves 367. In these grooves there are mounted, with sliding adjustment, bars 368 with castellations 373 defining between the mobile partitions (see also FIGS. 6 to 8).

The device comprises twelve grooves and four cylinders. The pistons of the central cylinders 361A, 361B (FIG. 4) are staggered through 180 relative to those of the two end cylinders 361C, 361D.

The mobile bars are in contact at their ends with the faces 371, 372 of cams 345, 346; these cams, during rotation of the rotor, transmit a rectilinear alternating movement to the bars; the effect of this movement is to obstruct or leave open each cylinder, the opening taking place when the partitions pass in front of the pistons.

FIG. 9, which shows the developed cylindrical surface corresponding to the cylinder passing through the mean diameter of the cams, indicated at MN on the left-hand part of FIG. 4, shows that work-chambers 375, 376 for the fluid are formed on both sides of each piston.

The device, used as a motor, functions as follows:

The pressurised fluid coming from the admission pipes, passes through the hollow axial portion 377 (FIG. 5) and the connector pipes 378, in order to penetrate through orifices 379 into the work-chambers 375 (FIG. 9). Bearing against the pistons, it pushes the partitions, closing the cylinders such as 368A (FIG. 3) in the direction of arrow F. The whole rotor is therefore moved in the direction of arrow F. The fluid trapped in chambers 376 escapes through orifices 381 and, through the connector pipes 382 and the hollow axial part 383, joins the exhaust pipes.

During the rotation, the mobile partitions such as 3683 (FIG. 3) are shifted towards the position opening the central cylinders, while the partitions such as 368C are shifted towards the position closing these cylinders. Thus there continuously reform, on either side of each piston, a chamber in which the fluid is at the admission pressure, and a chamber in which the fluid is at the exhaust pressure.

In zone I (FIG. 9) the partitions are in the position opening the central cylinders, 361A and 361B, and in the position closing the end cylinders 361C and 361D; they are immobile, and the faces of the cams are in planes perpendicular to the axis of rotation.

Zone II corresponds to the passage from the opening to the closing position of the central cylinders, and to the passage from the closing to the opening position of the end cylinders. During this manoeuvre, each partition is surrounded by fluid kept at a balanced pressure by:

ducts 385 (FIGS. 7, 8) connecting the internal and external faces of the partitions;

hollows 386 (FIGS. 3 and 9) in the face of the cylinders pertaining to the stator allow communication on both sides of the lateral faces when closing is complete, when this communication can no longer be ensured by the notches 373;

the configuration of said partitions is such that the effects of the pressure are eliminated in the longitudinal direction.

It should be noted that the penetration of the partition into the cylinder does not change the volume of the work-chamber, the partition removing from the cylinder, in its notch 373, a volume of fluid equal to the volume of the portion of the partition engaged in the chamber. The device can reach very high speeds of rotation, operating without jolts, therefore without vibrations and without noise, due to the balance in pressure of the fluid in contact with the mobile partitions, eliminating all frictional force, and due to the maintenance of the volume of the work-chambers'for the fluid.

In zone III (FIG. 9) the central cylinders are closed and the end cylinders are open, the partitions are immobile as in zone I, and the faces of the cams are in planes perpendicular to the axis of rotation.

Zone IV corresponds to a shift of the partitions in the opposite direction to that in zone II. The profile of the cam is symmetrical to that corresponding to this zone 11 relative to the median plane of zone III. Before the start of the sliding of the partitions, the hollows 386 a first member of stator 401, a second member or rotor 406 and a third member of rotor 414. The rotor 406 is rotatably mounted in the stator 401 coaxially therewith by means of two ball bearings 410 and 410 A.

The rotor 414 is rotatably mounted in the rotor 406 co-axially therewith by means of two further ball bearings 419, 419 A.

The rotor 406 is formed with four cylinders constituted by four annular grooves 407A, 407B, 407C and 407D cut in the outer cylindrical surface of said rotor. In the same outer cylindrical surface are cut a plurality of longitudinal guide grooves 408 in each of which is reciprocably mounted a mobile partition 409 adapted when they assume their longitudinal position represented at the top portion of FIG. 10, to close the cylinders 407B and 407C while the cylinders 407A and 407B remain open by virtue of notches such as 409A suitably provided in the partitions and having the same dimensions as the cross-section of the cylinders, or, when they assume their longitudinal position shown at the bottom part of FIG. 10, to close the cylinders 407A and 407D while leaving open the cylinders 4078 and 407C.

The mobile partition 409 is reciprocated axially by the action of helical cams 405 provided in the stator 401 in the path of travel of the extremities of the partitions.

In each of the four cylinders 407A to 407D a piston 404 is secured to the stator 401 (FIG. 11).

Two inlet orifices 402A and 402B (top of FIG. of the stator serve as fluid inlets to the cylinders 407A and 407D, respectively. A further orifice 402 BC (bottom of FIG. 10) in the stator serves as fluid inlet to the intermediate cylinders 402B, 402C. Such orifices 402A, 402B and 402BC open into the corresponding cylinders on one side of the pistons 404 (FIG. 11 Similar orifices opening on the opposite side of the pistons into the same cylinders serve for the outlet of the fluid. FIG. 11 shows one of said outlet orifices, namely orifice 4038 in communication with cylinder 407D.

Both rotors 406 and 414 make up a device of the type shown in FIGS. 3 to 9. This device also has four cylinwith two conduits 416B and 416C opening into the cylinders 4118 and 411C respectively.

Similarly, channel 41438 is in communication with two conduits (not shown) opening into the two cylinders 4115 and 411C respectively, while channel 414CC is in communication with two conduits (such as 416D, FIG. 11) opening into the two cylinders 411A and 411D, respectively. Y

The stator 401 and inner rotor 414 are formed with elongations 421 and 421B turning one inside the other in fluid-tight manner at one end of the device, coaxiality of said elongations being ensured by a bearing 422.

The longitudinal channels 414B and 414C of the rotor 414 are respectively in communication with a fluid inlet 402E anda fluid outlet 402F of the stator extension 421, through a hole 414E in the rotor 414 and an annular groove 421E in the elongation 421 and through a hole 414E in the rotor 414 and an annular groove 421E in the elongation 421, respectively,

Briefly, it may be stated that the outer stator 401 and the intermediate rotor 406 constitute a first assembly or first motor, while said intermediate rotor 406 and the inner rotor 414 form a second assembly or motor, both motors having in common the intermediate rotor 406.

The first motor operates under the control of the reciprocable partitions 409 actuated by the end cam faces 405 carried by flanges 418 while the second motor operates under the control of the reciprocable partitions 413 actuated by the corresponding end cam faces 405A also carried by flanges 418. The end cam faces 405 and 405A are coaxial with central shaft 414'.

The first assembly forms a motor which, in the pres-.

ent case, comprises four cylinders in each of which a piston is located. This motor functions similarly to the ing of the operation, and the possibilities of the device,

ders 411A, 411B, 411C, 411D (FIG. 10) formed by an- I The central part of the rotor 414 is hollow and divided into four longitudinal channels 4148, 4143B,

414C, 414CC (FIGS. 10, 11, and 12). Channel 4143 is in communication with two conduits 415 A and 415D opening into the cylinders 411A and 411D, respectively, while channel 414C is in communication which can be likened, for small angles of rotation, to a double cylinder having two pistons. In the following the first motor will be termed motor I, and the second motor motor II.

Motor I has its fixed part represented by rod 501 (FIG. 13) and piston 504, the latter being located in the left-hand part 506-1 of the double cylinder 506 which represents the mobile part.

The motor II has the part corresponding to its rotor schematically indicated by the right-hand part 506-2 of the common double cylinder 506, the stator being the piston 517 and its rotor 514.

The admissions and exhausts are represented by ducts 502 and 503 for the cylinder 506-1, and 515 and 516 for the cylinder 506-2,

The operation according to FIG. 14:

Points A and B are presumed to be fixed (fixed stator 501 and immobilised shaft 514). The fluid is admitted at 503 and evacuated at 504.

The fluid penetrating at 506-12 bears on the immobilised face of piston 504 and pushes cylinder 506 to the right. The fluid contained in space 506-21 is expelled through orifice 515, when there is suction in duct 516.

The part I of the device operates as a motor, while part II operates as a pump.

The operation according to FIG. 15:

Point A is fixed (fixed stator). The exhaust from cylinder 506-1 is effected in the part 506-22 of cylinder 506-2, the two cylinders being presumed to have the same cross-section. The exhaust ducts of motor I are the admission ducts of motor II, motors I and II being supposed of the same capacity, and the fluid incompressible.

The sum of volumes 506-11 and 506-22 is constant, involving the constancy of the sum of volumes 506-12 and 506-21 and, in consequence, invariability of the distance separating pistons 504 and 517. Point B does not move; in other words,'shaft 514 is immobilised when the various other parts of the device are operating under pressure.

Progressive passage into this position corresponds to braking and immobilisation of shaft 514.-

The operation according to FIG. 16;

The case represented by this Figure differs from the foregoing, in that the cross-section S of cylinder 506-1 is different from the cross-section S of cylinder 506-2 (motors I and II are of different capacities). The volume of fluid expelled from 506-11 is equal to the volume admitted at 506-22. S1 SL.

The distance covered by point B is equal to (1 L). It is linked to the value of the movement of the double cylinder by the relationship:

which is a constant of the machine illustrated. The movement of cylinder 506 is reduced.

The individual supply to the cylinders of motor I enables easy provision of a device having several rotary speeds of the shaft for the same output, the capacity of motor I depending on the number of cylinders supplied.

The operation according to FIG. 17:

Point A is fixed (fixed stator). The exhaust from cylinder 506-1 is effected in part 506-21 of cylinder 506-2, the two cylinders being presumed of the same cross-section. The exhaust ducts of motor I are the admission ducts 515 of motor II, the two motors being presumed of the same capacity, and the fluid used incompressible.

Cylinder 506-12 has increased by the volume of liquid expelled from 5013-11; as this excess of fluid is syphoned into 506-21, and there is equality between the volumes of compartments 506-12 and 506-21. The position of piston 517 is symmetrical with the position of piston 504 relative to the common base of the two cylinders; the movement of B is twice as great as that of the double cylinder.

For the device, this is translated by a shaft speed double that of either motor I or II, by the addition of their speeds.

This arrangement gives a motor with very high rotary speeds.

The operation according to claim 18:

This arrangement corresponds closely to that defined in FIG. 16. The motors are of different capacities.

The distance covered by point B is (l L); it is linked to the value of the movement of the double cylinder 506 by the relationship:

which is a constant of the machine shown schematically in FIG. 18. Taking account of the possibility of varying the capacity of motor I, this new arrangement of the supply to motor II doubles the number of rotary speeds of the shaft obtained with the solution in FIG. 16.

The operation according to FIG. 19:

The cylinder 506-1 is supplied under the same conditions as before; the admission and exhaust orifices of cylinder 506-2 communicate with each other (communication of the admission and exhaust of motor II, motor I being supplied normally).

By virtue of the communication between cavities 506-21 and 506-22, the fluid pressure is balanced on either side of piston 517. Apart from friction, all the axial force transmitted to rod 514 will move point 8, which is no longer linked to the double cylinder.

For the device, progressive passage into this position frees the rotation of the shaft (free wheel position).

The operation according to FIG. 20:

Cylinder 506-1 is still supplied under the same conditions, the duct connecting the admission and exhaust orifices being obstructed at C (motor I rotating, admission and exhaust ducts of motor II being closed.) The fluid from cavities 506-21 and 506-22, being incompressible, prevents any movement of piston 517 in cylinder 506.2. The piston and, in consequence, point B, move like the double cylinder. v

The devices shaft rotates at the speed of motor I, which affords supplementary possibilities of rotary shaft speed for the same discharge.

With inversion of the supply and exhaust in motor I:

All the cases studied proceed from the supply of motor I through orifice 503. Supply through orifice 502 reverses the direction of rotation of this motor, as a result of which there is no change as regards the case in FIG. 19; to reverse the direction of suction and delivery when functioning as a pump in FIG. 14; to change the direction of rotation of the shaft of the device in the case of FIG. 20, and to obtain the facility of braking and immobilisation of the shaft in the case of FIG. 17, the movement of B being 1 l 0 instead of l L 21, and to obtain the following additional possibilities:

The operation according to FIG. 21:

The exhaust from 5015-] supplies 506-2 through orifice 516. The volume of fluid expelled from 506-12 is equal to that expelled from 506-21. The position of piston 517 is symmetrical with the position of piston 504 relative to the common base of the two cylinders; the movement of B (-21) is twice as great as that of the double cylinder.

Thus new shaft speeds are obtained, equal but opposite in direction to those given by the arrangements of FIG. 17.

The operation according to FIG. 22:

The capacities of the motors are different, as in FIGS. 16 and 18. By virtue of the negative value (-l) of the movement of the double cylinder, the movement of B is equal to (1+L), this movement being linked to that of the double cylinder by the relationship:

The shaft speeds are equal to these obtained by the arrangements of FIG. 18, the direction of rotation being reversed.

The operation according to FIG. 23:

The capacities of the motors are different. The movement of the double cylinder being negative, point B is moved by the value (L-l). This distance (L-l) is linked to the movement of the double cylinder by the relationship:

the possibility of reversing the direction of rotation of the shaft of the device by inversion of motors I and II, as FIG. 24 shows, where admission and exhaust are inverted relative to FIG. 23.

Without being influenced by a difference in capacities, the shaft of the device would be moved at the speed of motor II with the arrangement in FIG. 25, which recalls that of FIG. 20, in which the shaft is at the speed of motor I. 7

Separate supply to both motors (FIG. 26):

If the supplies to motors I and II are separate, numerous combinations are still possible. The diagram in FIG. 26 gives an example.

Two motors are involved, with different capacities, which have valves in the admission ducts.

ln admission duct 503 to the large-capacity motor 506-1 there is mounted a valve 523 which is calibrated to open at the pressure calculated, at the speed of utilisation envisaged, to produce the required power. In duct 515 of the small-capacity motor 506-2, a valve 524 plays the part of a non-return valve forvthe fluid.

The operation is as follows: Depending on the valve of the resistant couple which the device must overcome, a certain pressure is established in the admission duct. If this pressure is lower than the calculated, the fluid penetrates only into the small-capacity motor, and this motor alone is used. If the pressure is higher than that calculated, the fluid penetrates into the largecapacity motor, which gives a motor couple higher than the foregoing. By virtue of the difference in section between the cylinders 506-1 and 506-2, the pressure at 515 is greater than the admission pressure, hence the usefulness of non-return valve 524.

As in the device in FIGS. 10 to 12, the individual supply to the cylinders permits variation of the capacity of motor I; the mounting on each individual supply duct of differently-calibrated valves offers wide possibilities of speed-couple combinations; it permits, during actual use, automatic adjustment of the speed and of the couple to the work required of the device.

Such devices have a whole series of advantages, notably:

they may be used as motors, pumps or compressors;

their symmetry relative to the two rectangular diametral planes permits rotation in both directions;

the assembly is compact and robust, enabling production of powerful, large-capacity devices;

the forces applied to the pistons are perpendicular to planes passing through the axis of rotation of the device, so that the couples transmitted to the output part are maximised;

if each annular groove contains several uniformlydistributed pistons, the transmission of the forces ap plied between the pistons and the rotating part is effected without parasitic reaction on the latter;

the device may be perfectly balanced both dynamically and statically; I

the volume of fluid admitted being proportional to the angle of rotation, the operation of the device causes neither vibrations nor noise;

the power-weight ratio is low;

they comprise very few different parts, a condition very favourable to economical construction;

thanks to their special design, they can achieve high speeds of rotation;

the large capacities of these devices enables them to I develop powerful couples. Each piston may be supplied separately, enabling the couple to be varied at will.

Nautrally, the invention is not limited to the embodiments described and illustrated; it is capable of numerous other variants available to the specialist, depending on the applications envisaged, without however going beyond the scope of the invention.

I claim:

l. A rotary pressurized fluid device usable as a pump, a compressor or a motor, comprising first and second coaxial annular units of revolution capable of turning one relative to the ohter on an axis common thereto and having mating faces in sliding engagement, at least one cylinder constituted by an annular groove of uniform cross-section formed coaxially between said two coaxial annular units in at least one of said mating faces, at least one piston secured to one of said two coaxial annular units and sealingly engaged in said at least one cylinder, radial guide grooves cut in the other of said two units transversely to said cylinder, mobile partitions slidably reciprocable in said guide grooves so as to divide said cylinder in cooperation with said piston into work-chambers, cams carried by said pistoncarrying unit for reciprocating said mobile partitions upon said units rotating one with respect to the other and fluid inlet and outlet orifices communicating respectively with two orifices located on each side of said piston, said other of said units being arranged inside said one of said units and forming a so-called second unit, said device further comprising a third coaxial unit arranged inside said second unit and also capable of turning relative therewith in a fluid tight manner, at least one further cylinder constituted by an annular groove of uniform cross-section formed between said second and third unit, at least one further piston secured to one of said second and third units and sealingly engaged in said further cylinder, further guide grooves cut in the other of said second and third units transversally to said further cylinder, further mobile partitions slidably reciprocable in said further guide grooves so as to divide said further cylinder together with said further piston into further work-chambers,

face, while said piston and further piston are carried by said first and third units, respectively.

3. A device as claimed in claim 2 in which said first and third units each have an axial elongation turning one inside the other in a fluid-tight manner beyond the second unit, said axial elongation of said first unit having further fluid inlet and outlet orifices permanently in communication, respectively, with said fluid inlet and outlet orifices of said third unit. 

1. A rotary pressurized fluid device usable as a pump, a compressor or a motor, comprising first and second coaxial annular units of revolution capable of turning one relative to the other on an axis common thereto and having mating faces in sliding engagement, at least one cylinder constituted by an annular groove of uniform cross-section formed coaxially between said two coaxial annular units in at least one of said mating faces, at least one piston secured to one of said two coaxial annular units and sealingly engaged in said at least one cylinder, radial guide grooves cut in the other of said two units transversely to said cylinder, mobile partitions slidably reciprocable in said guide grooves so as to divide said cylinder in cooperation with said piston into work-chambers, cams carried by said piston-carrying unit for reciprocating said mobile partitions upon said units rotating one with respect to the other and fluid inlet and outlet orifices communicating respectively with two orifices located on each side of said piston, said other of said units being arranged inside said one of said units and forming a so-called second unit, said device further comprising a third coaxial unit arranged inside said second unit and also capable of turning relative therewith in a fluid tight manner, at least one further cylinder constituted by an annular groove of uniform cross-section formed between said second and third unit, at least one further piston secured to one of said second and third units and sealingly engaged in said further cylinder, further guide grooves cut in the other of said second and third units transversally to said further cylinder, further mobile partitions slidably reciprocable in said further guide grooves so as to divide said further cylinder together with said further piston into further work-chambers, further cams carried by said further piston-carrying unit for reciprocating said further mobile partitions upon relative rotations of said second and third units, and further fluid inlet and outlet orifices communicating respectively with two orifices located on each side of said further piston.
 2. A device as claimed in claim 1, in which said second unit is hollow cylindrical with an inner and an outer cylindrical surfaces, said guiding grooves being cut in said inner cylindrical surface and said further guiding grooves being cut in said outer cylindrical surface, while said piston and further piston are carried by said first and third units, respectively.
 3. A device as claimed in claim 2 in which said first and third units each have an axial elongation turning one inside the other in a fluid-tight manner beyond the second unit, said axial elongation of said first unit having further fluid inlet and outlet orifices permanently in communication, respectively, with said fluid inlet and outlet orifices of said third unit. 